Video on demand (display) (VOD) are systems which allow users to select and watch/listen to video or audio content such as movies and TV shows when they choose to, rather than having to watch at a specific broadcast time, which was the prevalent approach with over-the-air broadcasting during much of the 20th century.
Simple machines are used to make work easier. They are used in various places and times in our lives. They include: the pulley, screw, wheel and axle, wedge, lever, and the inclined plane. Compound machines are made up of two or more simple machines. Materials Activity 1: Discovering Simple Machines Parents bring simple machines that they will demonstrate for students such as pliers, hammers, screwdrivers, wrenches, wire cutters, small crowbars, scissors, saws, garden tools,
Since ancient times, simple machines have been classified as lever, wedge, wheel and axle, pulley and screw. Sometimes the wedge and screw are considered special cases of the inclined plane, so there are either four or six simple machines. This is no more than an arbitrary and incomplete taxonomy.